The capability to reduce logic depth and improve frequency of digital circuits is a chief concern of customers of products that incorporate complex circuitry. Many different forms of circuits are used for products, by commercial and industrial customers, including Integrated Circuits (ICs), Complementary Metal-Oxide-Semiconductors (CMOS), electronic circuits, semiconductors, Very Large Scale Integrated Circuits (VLSI ICs), Application Specific Integrated Circuits (ASICs), circuitry on printed circuit boards (PCBs), microprocessors (also known as “processors”), nanotechnology circuits, and other types of circuits. With increasing functionality, circuitry is growing more dense and more complex, and increasing circuit frequency is becoming more important. High-performance digital logic circuits commonly include a multiplexer (also known as “mux”) combined with a flip-flop (also known as a “flip flop” or “flop”).
Especially for high-volume customers of ICs, having an ability to decrease logic depth translates directly into cost savings. For a multi-gigahertz processor, a logic depth improvement that saves just half of a gate delay may result in a substantial frequency speedup of 8 to 10 percent. Also, having a multiplexer flip-flop circuit that reduces real-estate on the IC may provide additional cost savings. For at least these reasons, there is a need for improved multiplexer flip-flop circuitry.